Sandpaper-drum.



H.'J. MITCHELL. SANDPAPER DRUM. APPLIoATIoN FILED JULY 5,1910.

Patented Feb. 6, 1912.

5 SHEETS-SHEET 1.

H. J. MITCHELL.

SANDPAPER DRUM.

APPLICATION FILED JULY 5,1910,

Patented Feb. 6, 1912.

5 SHEETS-SHEET 2.

H. J. MITGHELL.

SANDPAPBR DRUM.

APPLIUATION FILED JULX 1910.

Patented Fe H. J. MITCHELL. SNDPAPER DRUM. APPLIGATION FILED JULY a, 1910,

1,016,51 1. Patented Feb. 6,1912.

5 SHBETEQEHEET 4.

H. J. MITCHELL.

SANDPAPER DRUM.

APPLICATION FILED JULY 5,1910.

1,016,511. f f merma 1101.631912.

5 SHEETS-SHEET 5.

UNITED STATE-s PATENT OFFICE.

HARRISON J. MITCHELL. or BELOIT, WISCONSIN, ASSIGNOR To THE BERLIN 'MACHINE WORKS, or BELOI'I, WISCONSIN, A CORPORATION or WISCONSIN.

i SANnrArER-DRUM.

Specification of Letters Patent.

Application nld .Tuly 5, 1910. Serial No. 570,364.

My invention relates to sandpaper drums,

and has special reference to the mechanism for attaching and stretching-the sandpaper or other abrasivel material on the surface of the drum. l.

In my invention I employ a drum in the periphery of which there is a longitudinal groove. Placed within the periphery or shell of the drum, and on either side of the longitudinal groove, are a pair of abutment shafts against which the Opposite edges of the abrasive material are brought. Beneath the abrasive material is preferably placed a layer of felt or the like, one edge of which is attached to one of the abutment shafts, and the other edge of which is secured in position by means of a spring clamp which,

is held by a rod provided with a plurality of cam portions. Passing longitudinally through the shell, between the shaft on whichl the drum is mounted and the periphery of the same, is a clamping shaft preferably hollow and provided with a slot in its periphery and on which is mounted a plurality of spring clips, each clip consisting of a pair of leaf 'spring members which are normally separated from each other. These spring leaf members engage the abutment shafts above mentioned, and serve to hold the edges of the sandpaper or other abrasive material in proper position. This clamping shaft, on which -the spring clips are mounted, is rotatable by means of a suit-able crank which operates on al lever rigidly mounted on the shaft. On rotation of this clamping shaft, one member of each spring clip is separated from the edge of the abrasive material so that the samemay be removed or placed in position at will. One of the abutment shafts, above mentioned, is movable toward its companion abutment shaft by means of a suitable cam mechanism so that the two leaf spring members of each spring clip may be brought together, thereby serving to securely clamp the ed es of the abrasive material in position. hen thisoperation has been performed, the movtive view showi able abutment shaft is vrotated through the medium of a torsion spring, and a leaf spring projecting from the movable abutment shaft thereby engages the abrasive material and serves to tighten the same on the drum. These and other advantages of my invention will be more readily understood by reference to the accompanying drawings in which: v

Figure l is a side elevation and partly vertical longitudinal section -on a reduced scale taken on the line 1-1 of Fig. 4. Fig.

2 is a vertical longitudinal section on a re-r duced scale taken on line 2-2 of Fig. 4. Fig. 3 is an end elevation-of the drum and its associated parts, the cap at the end of the drum being removed. Fig. 4 is an end elevation Similar to that Shown in Fig. 8 except that certain parts have been removed in order to show the underlying parts with greater clearness. .Fig. 45 is a horizontal, longitudinal section on a reduced scale taken on line 5`-5 of Fig. 3. Fig. 6 is a fragmentary view of the clamping mechanism shown in Fig. 4, but with certa-in of the parts shown in another' position. .Fig 7 is a fragmentaryvertical longitudinal Section on the line 7-7 of Fig. 3. Fig. 8 is a fragmentary view `of the'clamping mechanism shown in Figs. 4 and 6 but with certain of the parts in a different position.. Fig. 9 is a perspective view of the felt clamping device. F ig.l 10 is a perspective view showing the method of securing the edge ofv the felt to the metallic 'strip which fits within one of the abutment shafts. Fig. 11 is an enlarged transverse Section on the line 11-11 of Fig. .5. Fig. 12 is a perspecthe resilient spring mechanism for rotatlng the .tightening shaft. Fig. 13 is a-perspectiv'e view of one of the rotatable key members which engage the ends of the spring within the tightening shaft. Fig. 14 is a perspective view of the crank shaft which operates the clamping shaft. Fig. 1.5 is a perspective view of the. slotted lever jengaged by the crank shaftshown in Fig. 14. Fig. 16 is a vertical longitudinal section through part of the tightening Shaft showing the torsion Spring and its engagin key members in position. Fig. 17 is a vertical section on the line 17-17 of Fig. 16.

Patented Feb. e, 1912.

1mb 2s through which the main shaft 29 passes. In the'periphery of the drum 25 is a longitudinalv slot- 30. On one end `of the drum 25 is provided a cap 31 having a hub 32 which is mounted on the main shaft 29. The other end lof the drum is similarly provided with the cap 33 which is mounted by mea-ns of its hub 34. on the same shaft. These caps are held in position by the cap screws31a shown in section in Figs. 3 and 4. Passing through the webs 2 7 of the sections 26, is the hollow abutment shaft34 having the longitudinal slot 35. This abutment shaft, as clearly shown in Fig. 4, is located just inside of one of the edges of the longitudinal slot 30. As most clearly shown in Fig. 10, the edge of a covering 36 of felt or other similar material is secured within the bent metallic strip 37 which is, in turn, held inposition within the abutment shaft 34, the felt passing through the slot in this shaft. The covering material 36 incloses the drum, and as clearly shown in Figs. 3, 4 and 1,1, passes over the opposite edge to that mentioned above of the slot 30.

Mounted near each end of the drum are the brackets 38 which act as retaining means for the cam rod 39. This rod, as best shown in Fig. 7, has the cam projections 40, and passes through suitable openings in the webs 27. The'upper edge of the cam rod 39 'engages the grooves 41 in the leaf springs 42,

4 which, as best shown in Fig. 2, are mounted between adjacent webs 27. Attached to one edge of each-,of the leaf springs 42 by means of the screws 43, is the retainingl rod 44 which, as best shown in Fig. 9, is provided with pointed projections4 45 on its upper surface. The retaining rod 44 is preferably made in a single piece, and passes completely through the drum 25. f y

It will be noted v that when the cam rod 39 is in the position shown in Figs. 4 and7, the leaf springs 42 are forced toward the periphery of the drum, and the retaining rod 44 is thereby caused to engage the edge of the felt covering 36 with suflicient pressure to hold the felt inposition. I f it isv desired to release the edge of the felt, the caps 31 and 33 are -removed from the drum, and the cam rod 39 is driven to the right, as indicated in Fig. 2, or to the left, as indicated in Fig. 7, so that the cam projections 40 are disengaged from the webs 27 and the brackets 38, and the cam rod allowed to move toward the center of the drum. The spring pressure acting through the leaf springs 42 is. thereby released from the retalning rod 44,-and theedge of the felt covering 36 may lreadily be removed from it-s -engagement with thefrod 44.

Passing through suitable openings in the webs 27, 'isi the clamping shaft 45 which is hollow 'and provided with the longitudinal slot 46. Mounted vwithin this clamping shaft, are the leaf springs 47, each of which has a pair of projecting clip members 48 and 49 whlch are normally separated from each other .when pressure is not exerted on the same. l' As best shown in Fig. 1, the leaf springs 47, having the two clip members 48 and 49, are mounted between adjacent webs 27. Rigidly mounted near the end of the clamping shaft 45, by means of the set-screw 50, is thc lever 51 having the longitudinal slot 52 and the pin 53 across its end, as best shown in Fig. 15. The short crank shaft 54, having the crank 55, is mounted on the end of shaft 56, which is, in turn, rigidly mounted in the Webs 27. The collar 57 prevents inward movement of the sleeved portion 58 of the crank shaft 54 and outward movement of the same is prevented by engagement of the inner surfaces of the two members of the crank 55 with the lever 51. The end of the crank shaft is provided with the slot 59 which may be engaged by a suitable key.' Rotatably mounted on the clamping shaft 45, are the wedging members 60, one of which is located in a position adjacent to each of the webs 27. Each of these wedging members is rigidly attached to the sleeve 61 inc losingthe tightenin shaft 61, the former acting also as an abutment shaft, as will be explainedV hereafter. Each of the wedging members 60, as most clearly shown in Figs. 11 and 12, is also provided with a beveled edge 62, these edges being engaged by the wedge shaped cams 63, mounted on the cam shaft 64. The end of cam shaft 64 is threaded at 65, and -has mounted thereon the sleeve 66 provided on its end withthe nut 67 which may be 'engaged by a suitable wrench. Inasmuch as the Wedgeshaped cam 6 passes through similarly shaped openin l 1n the webs 27, it will be apparent that on rotation of the sleeve 66,

the cam shaft. 64 will be moved longitudi` nally, and thereby correspondingly move the wedging members 60 on the clamping shaft 45 as an axis.

As most clearly shown in Figs. 11 and 12 the sleeve 61 is provided with a slot 68 through which project thetightening leaf springs 69 which are mounted within the hollow tightening shaft 61a. The end of the hollow tightening shaft 61 has a pair of slots on opposite sides which are engaged by one of the spring retaining key members 70. The shape of this key member is best shown in Fig. 13. The-ends of the torsion spring 71 engage the abutment portions 72 of the key members between which'this spring is located. A ratchet 73 is loosely mounted on the end of the sleeve 61 and is provided with a slot 74 which engages the projection 75 of the key member 70, located at the end of the sleeve 61. From the outside, the slot 74 of the ratchet 73 may be engaged by any suitable key and turned there- 130 by. 'A pawl 76 is *mounted on the Amain shaft 29 and serves to hold vthe ratchet 73 inrial is then wound around the periphery of the drum and is engaged by the retaining rod 44 in the manner as has already been described. -The edge of the sandpaper or other abrading material 78 is next placed against the abutment shaft or sleeve 61 where it is held in position by means of the clip member 49. The sleeve 66 has meanwhile been rotated so that the -wedgeshaped 4cams 63 have allowed the wedging members 60 to move to their maximum position to the right, as shown in Fig. 8. The abrading material is now 'wound around the drum and itsdisengaged edge 79, as shown in Fig. 8, is brought into a position opposite to the abutment shaft 34. The crank shaft 54 is now rotated so that the clamping shaft 45 is rotated in a contra-clockwise direction. The "clip member 48 is now brought into engagement with the edge 79 of the sandpaper and holds the same against-the abutment' shaft 34, the clip member 49 meanwhiley remaining in engagement with the edge of the abrading' material 78 which `is 'incontact with the sleeve 61. The sleeve 66 isnow rotated in order to move the `cam shaft 64's'0 that the wedge-shaped cams 63 will forcethe wedging members 60 to thev left, as shown in Figs. 4, 6 and 8, until the two clip members 48 and 49 are brought into contact with each other, and firmly hold' the edges of vthe sandpaper in contact with't'he abutment shafts 34 and 61. In order to lstill further tighten the sandpaper, the ratchet 73 isy now rotated in a contra-clockwise direction by the engagement of a suitable key with the slot 74 of this ratchet, the eifect of such rotation being to rotate the tightening shaft 61a within the sleeve 61 thereby carryin the leaf spring 69 intocontact with the san paper, as clearly indicated in Fig. 6. It will be noted that this action kis effected through the medium of the torsion spring 71 so that' the engagement of the leaf spring 69-with the sandpaper is of a resilient nature.

It will be apparent to those skilled in the art that many changes could be made in the detailed construction of the parts which I have described without departing from the spirit of my invention.

What Iclaim'is;

1. In a device of the Vclass described, lthe combination of a longitudinally-grooved shell, an abutment in said shell, a clampingy meinberlin said shell,vmeans for `moving said 'clamping member toward said abutment to clamp the edge of a sheet of abrading material between said parts, and means for retaining the edges of said sheet', during adjustment, in contact with said abutment ,and said clamping member. l

2. In a device of theclass described, the

combination of a shell having a longitudinal groove -in its periphery, abrading material wrapped around said shell, means for retaining the edges of the abrading material in said groove, a tightening shaft passing through said shell, a bearing sprlng attached to and projecting from said shaft, and means for rotating said shaft thereby bringing the bearing spring into contact the same, substantially as described. 4

3. yIn a device of the class described, the combination .of a shell having a longitudinal lgroove in its periphery, abrading material Wrapped `around said shell, means for re'- 'tainlng the edges of the-abrading material in said groove, a tightening shaft passing .through said shell, a bearing sprlng attached to and projecting from said shaft,

yand resilient means for rotating said shaft thereby ,bringing the bearing spring into contact `with the abrading material and tightening;l the same, substantially as described.

4. In al device ofthe class described, the

combination".v of a cylindrical drum having a ,thereby retain` the edges ofsaid abrasive material in osit-ion, and meansforactuating said 'spring clip members, substantially as described.

5. Ina device of the class described, the combination of a cylindrical drum having a longitudinal groove in its periphery, abrasive material inclosing said drum, a pair of abutment members adjacent to said groove, a clamping shaft within said drum,

spring clip members mounted on said clamping shaft and adapted to engage said abutment members thereby holding opposite ,with the abrading material and tightening edges of the abrading material in contact with said abutment members, and means for rotating said clamping shaft, thereby causin'g engagement and disengagement of the clip members from said abutment members, substantially as described.

6J In a device of the class described, the

combination of a cylindrical drum having a au bearing spring `mounted in one of said 'abutment members,- meansfor actuating `said bearing spring, a clamping shaft, clipv members mounted in said shaft and engaging said abutment members and thereby retaining in position the edges of'said abrading material, means for rotating said clamping shaft'thereby causing engagement and disengagement 'of the clip members with said abutment members, and means for moving one of' ,sa-id abutment members thereby bringing the clip members into contact with eachother and firmly clamping the abrading material in position,'substa1 itially asdescribed. n

' 7. In a, device of the class described, the combination'of a Icylindrical drum having a longitudinal groove inits periphery, abutment members adjacent to said groove, abrading material inclcsing said drum and passing over saidvabutmen't members, means for engaging the edges of said'abrading material and holdingI them in contact with the abutment members,'and cam actuated means for moving one of said abutment members, thereby bringing the engaging means into contact witheach other and firmly clamping the edges of the 'abrading materialbetween said engaging means and the abutment members, substantially as described.

8. In a device of the class described, the combination of a cylindrical drum having a longitudinal groove in its periphery, abutment members adjacent to said groove, abrading material inclosing said drum and passing over 'said' abutment members, means" for engaging the edges' of said abrading material and holding them in contact with the abutment members, cam actuated means for moving onev of said' abutment members, thereby bringing the engaging means into contact with each other and firmly clamping the 'edges' of the abrading material between said engaging means and the abutment members, and a bearing spring associated with one of said abutment members, said bearing spring adapted to engage the abrading ma-l4 terial and tighten the same onthe "drum,

substantially as described.

ing through Asaid drum, clip members mount* ed onsaid clamping shaft, means Vfor rotatf' ing said clamfpingshaft and thereby bringing the clip members into contact 'with ."the

,abutment members, a Wedging member rigidly mounted on said clamping shaft and rigidly connected with one of said abutment members, 4and cam means for moving said wedging member thereby causing said abut- Ement member to bring the clip members into 'contact with each other and firmly clamp :the edges ofthe abrading material between said clip members and said abutment members, substantially as described.

10. In a device of the class described, the fcombination of a longitudinallygrooved shell, al pair lof members between which the` edges ofran abrading sheet may be clamped, fmeans for temporarily holding the sheet, .during adjustment, and means for causing ,said members vto approach each other and :grip said edges.

j 11. In a device of the class described, the combination of a cylindrical drum having a ilongitudinal groove in its periphery, a re'- isilient covering for said drum, an abutment member adjacent to the longitudinal groove, means for retaining one edge of the resilient ,covering within said abutment member, a retaining rod adapted to engage the opposite edge of said resilient covering, resilient fme'ans for holding said retaining ro'd in polsiti'on, and a cam rod for regulating the enggaging pressure of said retaining vrod on said covering, substantially as described.

12. In a device of the class described, the iccmbination of a cylindrical drum having fa longitudinal groove in its periphery,

,'abrading material inclosing said drum,

means for securing the edges' of said abrading material in position Within said groove, fa tightening shaft passing `longitudinallyl `through said drum, a bearing' member mounted on said shaft and adapted to en- ;gage said abrading material, and resilient Qmeans constantly tending vto rotate said 'tightening vshaft thereby 'tightening the :abrading material on said drum, substantially as described.

I 13. In a de'vice of the class described, the combination of a, cylindrical' drum having a longitudinal groove in its' periphery, abrading material -inclsing said drum, means for`securing the edges of said abrading material Within said groove, a tighten- 'ling shaft passing longitudinally through 'said drum` and having a projection adapted v to engage said abrading material', a sleeve 9. In a device of'the class described, the 4combination of a cylindrical drum having a longitudinal groove in its periphery, abut-y vinclosing said tighteningv shaft, and resilient means for Lrotating said tightening shaft independentl'y of said sleeve'thereby tightenl ing' the abrading material on said drum, substantially as described.

14. In a device of the class described, the combination of a 'longitudinally grooved shell, a pair of' relatively movable members between which the edges of an abrading sheet may be clamped, springsbetween said .members `for temporarily holding, during' adjustment, the edges of the sheet against said members, kand means for forcingsaid members toward each other.

15'. In a device of the class described, the combination of a cylindrical drum, abrading material inclosing said drum, a tightening shaft passing through said drum and having a projection adapted to engage said abrading material, a sleeve inclosing 'said tightening shaft, a torsion spring in said sleeve, key members on opposite ends of said spring, one of said key members engaging the end of the tightening shaft, and means for rotating the second key member thereby rotating said tighteningfshaft and causing resilient engagement of its projecting member With the abrading material and t-ightening the latter on the drum, described.

16. In a device of the class described, the

substantially as combination of a cylindrical drum,- abrading material inclosing said drum, a tlghtening shaft passing through said drum and haV-.

Spring, one of said key members engaging.

the end of the tightening shaft, and a paWl controlled ratchet engaging said second key member and adapted to rotate the same thereby rotating said tightening shaft and causing resilient engagement of said projecting member with the abrading material and tightening the latter on the drum, substantially as described.

HARRISON J. MITCHELL. Witnesses:

T. A. HoRsTMANN,

TELLA SOLIEN. 

